The measurement, description, and mapping of planes, lines, and angles is foundational to the geological sciences and to many other field-based disciplines. As illustrated in FIG. 1, geological structures 4 and landforms have a three dimensional nature that is measureable in reference to three orthogonal axes: a horizontal reference plane 6 with X- and Y-axes, and a vertical plane, usually referred to as the Z-axis or elevation. The horizontal plane 6 is typically visualized as a level water surface and described as X, Y map coordinates or a compass bearing between two points. The vertical plane is perpendicular to the horizontal plane and running through a line, whether a line of directional bearing between two points or the lineation of a feature being measured. Methods and apparatus used to measure geological structures are described in Coe, Angela. L. (ed.), Geological Field Techniques, Wiley-Blackwell, The Open University, 2010, which is incorporated herein by reference in its entirety.
To measure, record, and map the orientation of a geological structure, such as the bedding plane 4 illustrated in FIG. 1, geoscientists measure the bedding plane in reference to the horizontal reference plane 6, in both the horizontal and vertical planes. Strike 8 is the directional bearing of a line produced by the intersection between a plane substantially parallel to the surface of the geological structure 4 in question and the horizontal plane 6. Strike 8 can have two possible bearings that are 180 degrees from each other. Dip 10 is a vertical angle between the plane parallel to the surface of the bedding plane 4 in question and the horizontal plane 6. Dip 10 consists of an angle and a singular direction, with dip 10 direction 11 always perpendicular to strike 8. Dip direction 11 is often described as a general bearing quadrant. The complete description of a plane consists of strike 8 (bearing), dip (angle) 10, and dip direction 11.
To measure, record, and map the orientation of a line or lineation 12 of a geological structure 4, geoscientists measure the lineation 12 in reference to a vertical reference plane, in both the horizontal and vertical planes. Trend 14 is the directional bearing of the vertical plane that intersects the lineation 12. Trend 14 has a singular direction if the lineation 12 is non-horizontal, with trend pointing in the direction that the lineation plunges down. Plunge 16 is a vertical angle between the lineation 12 and the horizontal plane 6, measured in the vertical plane of trend. Plunge 16 only consists of an angle because trend 14 already states the direction of the lineation 12. The complete description of the lineation 12 consists of trend 14 (bearing) and plunge 16 (angle).
To measure, record, and map a directional bearing between two points, geoscientists measure compass direction or azimuth in the horizontal plane 6. Usually the directional bearing is measured from the point where one is standing to another point in the landscape. Bearing can be stated in azimuth format (0-360 degrees, where 0° is North and 180° is South) or in quadrant format (NW, NE, SE, SW, with angles stated in relation to North or South within relevant quadrants).
To measure, record, and map an angle of inclination between two points, geoscientists measure angles in the vertical plane. This measurement is usually performed from a viewer's eye height with a device that measures angle up or down to an object in the landscape. Zero degrees is a horizontal angle and 90 degrees is a vertical angle.
The measurement of planes, lines, azimuths, and angles in the field is an important skill and methodology for geologists, surveyors, engineers, and workers of other field-based disciplines. For over 100 years, these measurements have primarily been performed using a pocket transit, a small, lightweight tool originally invented by Canadian mining engineer D.W. Brunton in 1894. The pocket transit consists of a magnetic compass with a needle that always seeks magnetic North, a perimeter divided into quadrants (NW, NE, SE, SW) or azimuth (0-360 degrees), a bull's-eye level to ensure accurate compass readings, and an inclinometer mechanism with a protractor dial and inclinometer level to measure angles in the vertical plane. Most models contain a hinged lid to protect the compass face, with a mirror inside the lid cover that is used for sighting in combination with a fold-out sighting arm opposite the lid hinge. The lid can only rotate around one axis formed by a solid pivot pin of the hinge.
Improvements upon the original model continue to be made by the Brunton Company of Riverton, Wyo., including a magnetic needle mounted on a jewel bearing, magnetic damping of the needle to speed up measurements, adjustment for magnetic declination, and a button that locks the magnetic needle for measurement readings and for protection of the assembly when the lid is closed during transport. One Brunton transit model has hinge dials that can be used to measure dip angle while simultaneously measuring dip direction. Brunton pocket transits are oriented with compass North pointing perpendicular and away from to the lid hinge, parallel to the fold-out sighting arm. Many of these features are disclosed in U.S. Pat. Nos. 526,021, 4,095,348, 4,175,333, 4,438,568, 4,700,490, 6,357,128, 6,516,526, 6,647,633, 8,322,041, and U.S. Design Pat. No. 290,093, which are each incorporated herein by reference in their entireties. These pocket transits and prior art compasses have been found to have several deficiencies which limit their usefulness and make taking accurate measurements difficult.
Measuring strike and dip of a plane with prior art compass models can be accomplished by either a direct contact method or a sighting method. Examples of methods of measuring geological structures with a Brunton Geo Transit are illustrated and described in “Brunton, Geo Transit Operator's Manual,” and further identified as “11-GEO rev. 0109” (copyright 2001) available at https://cdn.shopify.com/s/files/1/0217/7948/files/Transit Manual.pdf?17230039625499351574 (last visited May 30, 2015), which is incorporated herein by reference in its entirety.
The direct contact method of measuring strike and dip with a Brunton type transit requires at least three separate compass orientations and measurements. First, the bearing 18 of strike 8 is measured by holding the side edge of the compass 20 along the plane of the geological structure 4, as illustrated in FIG. 2. The compass 20 is then leveled and the location of the magnetic needle on the perimeter ring is read to determine the bearing 18 of strike 8. Next, the angle of dip 10 is read by turning the compass 90 degrees and placing its edge on the plane of the geological structure 4, as illustrated in FIG. 3. The inclinometer arm on the back of the compass 20 (not illustrated) is adjusted until the inclinometer bubble level in the compass face is level. The dip angle is then read from the inclinometer dial 22. Finally, dip direction is measured by holding the compass face 21 horizontal again and placing the hinge or lid 24 of the compass 20 against the plane formed by the geological structure 4 with the compass pointing in the direction of dip, as illustrated in FIG. 4. An alternate direct contact method, also illustrated in FIG. 4, is to measure dip angle and dip direction only. Strike may then be calculated because strike is always perpendicular to dip. Several compass models exist that have hinge dials 22 (or hinge inclinometers) that can be used to measure dip angle while dip direction perpendicular to the hinge axis is simultaneously measured with the compass face.
Unfortunately, it is common to make mistakes when measuring strike and dip of a plane as the compass 20 is moved using the direct contact method. Obtaining an accurate strike measurement is further inhibited by uneven bottom surfaces on many prior compass models. These uneven surfaces interfere with leveling of the compass to obtain a strike measurement. The direct contact method is especially problematic when measuring planes of less than 10 degree dip.
The sighting method for measuring strike and dip, illustrated in FIG. 5, is used when direct contact of the compass 20 with the plane being measured cannot be achieved and when a person can move to a position in line-of-sight along the plane's strike. A level line of sight to the plane is found. The directional bearing (strike) is measured along that level line of sight. This requires two steps and compass orientations. Dip angle is measured by holding the compass 20 at arm's length, aligning either a top or bottom edge of the compass with the plane of the geological structure 4, and adjusting the inclinometer arm (not illustrated) and level to read the angle on the inclinometer dial 22. Dip direction is estimated or calculated based upon strike and measured dip angle. Measuring strike and dip from a distance requires at least four separate compass orientations.
Measuring trend and plunge of a lineation with known compass models (not illustrated) can also involve a direct contact method or sighting method. The contact method of measuring trend and plunge requires two different compass orientations and a second object. This method is one of the most challenging to visualize, understand, and teach, and leads to many errors when lineations are on near-vertical or overhanging faces. The direct contact method is best performed by measuring plunge angle first. The compass is set on one of its edges along the lineation. The clinometer arm and level are then used to quantify plunge angle. Next, trend is measured. A second object, such as a non-metallic clipboard or notebook, is often required to help create a vertical plane that is measureable. The second object is placed directly along the lineation, and the compass edge is held flush against the object or aligned with the object. When the bull's-eye level on the compass face is level, the second object is vertical, and the bearing in the direction of down-plunge can be measured (trend).
Measuring trend and plunge using the sighting method requires that a person can place himself in line-of-sight along the trend of the lineation and then move to place himself perpendicular to the lineation to measure plunge. Because it is difficult, and sometimes not possible, to be perpendicular to the lineation, measuring plunge using the sighting method is rarely used. A directional bearing of trend can be measured with a level compass face, then a sighted measurement of plunge angle can be measured by aligning the compass edge at arm's length along the lineation. Measuring trend and plunge using the sighting method requires two different compass orientations, and as stated above, is rarely used due to inaccuracy.
The traditional method of measuring a directional bearing of an object 29 with a known compass 20 can be performed at either waist height or eye height. The waist height method of measuring a directional bearing 18, illustrated in FIG. 6, involves holding the compass 20 away from metallic belt buckles at approximately waist height. The user then looks down on the compass face 21 and sights the object 29 in question by using a mirror 27 positioned in the compass lid 24 and a fold-out sighting arm 28. The simultaneous requirements of finding the object's reflection 29A upside-down in the mirror 27, aligning the object 29 with the sighting arm 28, leveling the compass face 21 with a bull's-eye level, and reading the compass needle are challenging to even the seasoned professional.
The eye height method of measuring a directional bearing 18, illustrated in FIG. 7 involves turning the compass 180 degrees so that the lid 24 is positioned away from the user, bringing the fold-out sighting arm 28 close to the user's eye, and arranging the lid 24 so the compass face 21 is visible to the user in the mirror 27. An object is sighted through an aperture 25 (illustrated in FIG. 8) in the mirror 27 and lid 24 or through a small sight 26 attached to the lid 24. The user must then level the compass 20 and read a reflection of the compass needle in the mirror 27. This method is also quite challenging and open to error, since the opposite end of the magnetic compass needle needs to be read.
Measuring a vertical angle with known compasses is performed at eye height by holding the compass 20 on edge, as illustrated in FIG. 8. The fold-out sighting arm 28 is placed near the user's eye, the mirror in the lid 24 is arranged so that the inclinometer bubble level and dial are visible reflected in the mirror, and the object is sighted through peep hole or aperture 25 formed through the lid 24 and the mirror 27. The user adjusts the clinometer arm on the back of the compass 20 until a bubble level in the compass face 21 is level. The angle is then read as a reflection of an inclination dial 22 (shown in FIG. 5) in the mirror 27 of the lid 24. Alternatively, the user can read the angle by moving the compass 20 away from the user's eye and looking at the inclination dial on the compass face 21. While a straightforward method, certain lighting situations make it very difficult to see the inclinometer bubble level.
Known compasses present many challenges which can lead to improper use of the tool or inaccurate measurements. Users learning to use known compasses are often frustrated by the multi-step, awkward processes involved. Many of the measurements using traditional compasses are not intuitive or easily visualized. Measurements must be carefully recorded in the field, and significant error is introduced when either multiple steps and compass orientations are involved, or when the compass is put away or placed on the ground between measurements to allow for recording. Even seasoned professionals encounter situations where traditional compasses are almost impossible to use or read.
Several attempts have been made to improve the design of compasses and geologic formation measuring devices. One example is U.S. Pat. No. 1,468,368, which describes a telescope pivotally secured to a cover of surveying instrument. Other examples are U.S. Pat. Nos. 1,944,104 and 4,020,559 which describe sight openings formed through a housing of the compass. Another example is U.S. Pat. No. 6,701,631, which describes a compass adapted to measure direction and dip with or without assistance of the earth's magnetic field. Yet another example is provided in U.S. Pat. No. 8,393,086, which describes an apparatus for measuring trend and plunge and includes a rod operable to be disposed parallel to a lineation. Still another design, described in U.S. Patent Publication No. 2013/0239422, includes a compass in a measuring unit pivotably mounted to a support piece. Each of these Patents and Patent Publications are incorporated herein by reference in their entirety.
Various other prior art compasses, components of compasses, and devices for measuring geologic structures have been described. Examples are provided in U.S. Pat. Nos. 709,046, 725,073,921,889, 997,222, 1,468,368, 1,474,394, 1,571,697, 1,936,846, 2,019,411, 2,027,952, 2,108,263, 2,111,829, 2,141,173, 2,358,589, 2,487,044, 2,498,083, 2,680,297, 2,822,618, 2,857,679, 2,878,578, 2,914,862, 3,160,961, 3,184,854, 3,191,306, 3,217,420, 3,876,313, 4,081,912, 4,158,260, 4,395,828, 4,622,750, 6,094,830, 6,145,209, 6,701,631, 6,739,063, 7,134,213, 7,331,114, 8,296,960, 8,322,041, 8,393,086, 8,640,351, 8,695,225, U.S. Patent Application Publication No. 2003/0110651, U.S. Patent Application Publication No. 2013/0014397, U.S. Patent Application Publication No. 2013/0014398, U.S. Patent Application Publication No. 2013/0239422, U.S. Patent Application Publication No. 20140182149, U.S. Design Pat. 369,982, U.K. Pat. No. GB 366210, World Intellectual Property Organization Publication WO 2013/187584, European Patent Application Publication No. 0668484, and European Patent Application Publication No. 2546606, which are each incorporated herein by reference in their entirety. The compasses and surveying devices described by these patents do not solve the problems of known compasses described above.
These designs fail to teach or describe various novel features of the compass of the present invention. Furthermore, many previous attempts to improve the design of known compasses have involved major changes to the design of the compass, or added additional elements to the compass, increasing the size and complexity of the compass and making the compass more easily damaged in the field. Accordingly, there is an unmet need for a more intuitive compass that requires fewer steps for each type of measurement.